Feature #15722

Updated by sawa (Tsuyoshi Sawada) over 1 year ago

I often want to use `===` to match a single object on the right side against multiple objects on the left, as is used in `case`-constructions, just to return a truth value, and end up writing like this: 

 bar # => "bar" 
 flag1 = case bar; when "foo", "bar", "baz"; true; end # => true 
 flag2 = case bar; when Symbol, String; true; end # => true 

 I propose `Kernel#case?` that should work like this: 

 bar # => "bar""foo", "bar", "baz") # => true"qux") # => false, String) # => true # => false # => false 

 It is similar to Rails' `in?`, but it differs from it in that it uses `===` for comparison, not `==`. 

 Or, alternatively, allowing `Kernel#instance_of?` and `Kernel#kind_of?` to allow multiple arguments may be a compromise.